Strains of Ehrlich ascites tumor cells of mice will be collected. The strains differ in chromosome number, growth rate, and enzyme profiles, especially in the activity of glycerol-P dehydrogenase (GPDH). The metabolism of glucose, lactate and pyruvate by strains with high and low levels of GPDH will be compared. Incorporation of C14 and tritium from these labelled substrates into products, and a complete carbon and hydrogen balance will be obtained. One strain, H, was previously found by us to synthesize glycogen from glucose, but there was no glycogen synthesis in other strains. The activities of enzymes of glycogen synthesis and utilization in this and other strains will be measured. The effect of dietary and hormonal factors on the induction of glycogen synthesis will be studied. The oxidation of lactate and pyruvate by strains with different levels of GPDH will be studied. The oxidation of cytosolic NADH and mechanism of cytosolic reducing equivalents transfer to mitochondria will be studied by comparing effects of a series of inhibitors on lactate and pyruvate oxidation. The role of the glycerophosphate shuttle and other pathways in the transfer of reducing equivalents will be examined.